/*
** $Id: lparser.h,v 1.70 2012/05/08 13:53:33 roberto Exp $
** Lua Parser
** See Copyright Notice in lua.h
*/

#ifndef lparser_h
#define lparser_h

#include "llimits.h"
#include "lobject.h"
#include "lzio.h"


/*
** Expression descriptor
*/

typedef enum {
	VVOID,	/* no value */
	VNIL,
	VTRUE,
	VFALSE,
	VK,		/* info = index of constant in `k' */
	VKNUM,	/* nval = numerical value */
	VNONRELOC,	/* info = result register */
	VLOCAL,	/* info = local register */
	VUPVAL,       /* info = index of upvalue in 'upvalues' */
	VINDEXED,	/* t = table register/upvalue; idx = index R/K */
	VJMP,		/* info = instruction pc */
	VRELOCABLE,	/* info = instruction pc */
	VCALL,	/* info = instruction pc */
	VVARARG	/* info = instruction pc */
} expkind;


#define vkisvar(k)	(VLOCAL <= (k) && (k) <= VINDEXED)
#define vkisinreg(k)	((k) == VNONRELOC || (k) == VLOCAL)

typedef struct expdesc {
	expkind k;
	union {
		struct {  /* for indexed variables (VINDEXED) */
			short idx;  /* index (R/K) */
			lu_byte t;  /* table (register or upvalue) */
			lu_byte vt;  /* whether 't' is register (VLOCAL) or upvalue (VUPVAL) */
		} ind;
		int info;  /* for generic use */
		lua_Number nval;  /* for VKNUM */
	} u;
	int t;  /* patch list of `exit when true' */
	int f;  /* patch list of `exit when false' */
} expdesc;


/* description of active local variable */
typedef struct Vardesc {
	short idx;  /* variable index in stack */
} Vardesc;


/* description of pending goto statements and label statements */
typedef struct Labeldesc {
	TString *name;  /* label identifier */
	int pc;  /* position in code */
	int line;  /* line where it appeared */
	lu_byte nactvar;  /* local level where it appears in current block */
} Labeldesc;


/* list of labels or gotos */
typedef struct Labellist {
	Labeldesc *arr;  /* array */
	int n;  /* number of entries in use */
	int size;  /* array size */
} Labellist;


/* dynamic structures used by the parser */
typedef struct Dyndata {
	struct {  /* list of active local variables */
		Vardesc *arr;
		int n;
		int size;
	} actvar;
	Labellist gt;  /* list of pending gotos */
	Labellist label;   /* list of active labels */
} Dyndata;


/* control of blocks */
struct BlockCnt;  /* defined in lparser.c */


/* state needed to generate code for a given function */
typedef struct FuncState {
	Proto *f;  /* current function header */
	Table *h;  /* table to find (and reuse) elements in `k' */
	struct FuncState *prev;  /* enclosing function */
	struct LexState *ls;  /* lexical state */
	struct BlockCnt *bl;  /* chain of current blocks */
	int pc;  /* next position to code (equivalent to `ncode') */
	int lasttarget;   /* 'label' of last 'jump label' */
	int jpc;  /* list of pending jumps to `pc' */
	int nk;  /* number of elements in `k' */
	int np;  /* number of elements in `p' */
	int firstlocal;  /* index of first local var (in Dyndata array) */
	short nlocvars;  /* number of elements in 'f->locvars' */
	lu_byte nactvar;  /* number of active local variables */
	lu_byte nups;  /* number of upvalues */
	lu_byte freereg;  /* first free register */
} FuncState;


LUAI_FUNC Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
								Dyndata *dyd, const char *name, int firstchar);


#endif
